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ICT SYSTEMS

1.1 Input devices: These are devices that are used to input data into the computer.

Computer Keyboards:

Used for inputting text or instructions to the computer. The QWERTY keyboard=called like this because of the first letters in the top line; Is the most common keyboard, but not the cheapest. The DVORAK keyboard= named after his inventor; has a much more efficient layout, much easier to use but it is unlikely to increase in use.

The Ergonomic keyboard= these keyboards are shaped so that the user is less likely to suffer from RSI.

Concept keyboard= consist of a tray with an overlay sheet on it. This sheet has symbols, letters or numbers which the user presses to choose what he wants, like a normal keyboard. Normally used by people with disabilities.

Advantages: They allow accurate entry of data.

They allow quick entry of text.

They are robust devices.

Disadvantages: Some can be difficult to use for people with disabilities.

Not very quick for entering data compared with other devices (barcode reader).

They take up more space than other input devices.

Numeric Keypads: It is used to enter numbers, although letters can be entered by using a function key. They are used in places where only numbers have to be enteres like on; mobile phones, when insertng the PIN and CHIP, etc.

Advantages: They are small and compact so they can be carried around easily.

Many devices can be connected to the same computer.

Easy to cover up when entering a pin.

Disadvantages: Difficult to enter text.

Too small for numbers to be used effectively.

Mice: It is a pointing device used by the user to control the position of the pointer and to choose what to do. They can be used to draw objects.

Advantages: Faster entry of the chosen option.

Fast navigation through slideshows and websites.

Smaller and more compact than keyboards.

Disadvantages: Difficult for people with disabilities.

Can be damaged fearly easily.

Difficult for entering data.

Touchpads: Has the same use as a mouse, but this is on a laptop.

Advantages: Faster entry of the chosen option.

Fast navigation through slideshows and websites.

Don't have to be plugged in.

Disadvantages: Difficult for people with disabilities.

Difficult to control compared to mouse.

Difficult for entering data.

Tracker balls: It is a large ball in the middle of the device that is controlled by using the palm of your hand and enables the user to control the pointer on the screen.

Advantages: They don't require the fine control that a mouse does.

Easier for people with disabilities or RSI to use.

They are fixed, so they can't be lost or knocked accidentally.

Disadvantages: Difficult to enter data that the button hasn't been programmed for.

Slower than a mouse.

Video digister: It is used to input video into a computer from a television or video camera. For the computer to understand these signals, the data has to be transformed to digital from analogue; using an analogue-to-digital convertor.

Remote controls: It is used to control other devices remotely by emising an infrared signal. There are buttons to choose different options.

Advantages: They can be at any distance from the ddevice and still be used.

People with walking difficulties find it easier.

Disadvantages: People with RSI or difsabilities can find it hard to use.

If there's something in between, the signals won't work.

Joysticks: Has the same function as a mouse or trackerball. It is a stick that is gripped by the hand and used to control the screen. There are buttons.

Advantages: Faster entry of chosen option compared with typing on a keyboard.

Used to control objects on three dimensions.

Disadvantages: Difficult for entering data other than menu choices, etc.

It's more difficult to control the pointer.

Touch screens: The user can choose from options on the screen by pressing on it.

Advantages: They allow faster entry of the chosen option.

Easier to select options than by using a mouse.

Easy for people with disabilities.

Less likelihood of selecting the wrong option.

Disadvantages: Difficult to enter data other than from a list.

Rsi could result from the use of the finger.

Magnetic strip reader: Used to read information from magnetic strips found on plastic cards.

Advantages: Faster entry of data compared with a keyboard.

Data entry is more accurate compared with a keyboard.

Data entry is more secure than with a keyboard.

Prevents entry to restricted areas without a card.

Disadvantages: If the strip is damaged, data has to be entered manually.

If the strip is damaged or lost, the holder cannot enter a room or use the data.